Anthropologist unlocks mystery of ancient blue pigment used by Mayans

Friday

Mar 28, 2008 at 12:01 AMMar 28, 2008 at 11:38 AM

It’s a rich azure shade. The hue of the brightest blue sky or clear, brilliant Caribbean waters. It’s a color that has permeated Dean Arnold’s subconscious, tinted his thoughts and stained his professional work for decades.

Jessica Young

It’s a rich azure shade. The hue of the brightest blue sky or clear, brilliant Caribbean waters. It’s a color that has permeated Dean Arnold’s subconscious, tinted his thoughts and stained his professional work for decades.

Arnold, an anthropologist at and alumnus of Wheaton College in Illinois, has been transfixed with an ancient pigment known as Maya Blue, a nearly indestructible dye painted on offerings to the deities, pottery and temple murals across Mesoamerica from about 300 A.D. to 1500 A.D.

“There has been a deep fascination with the legendary substance in my field,” he said. “We’d discovered that Maya Blue was used for human sacrifices in highly ritualistic ceremonies where they were smeared from head to toe, and it had medicinal properties. So you’ve got the lure of violence, sex and drugs.

“But no one knew how the pigment was actually produced at the time of those civilizations,” Arnold said.

Researchers have long recognized the composition of the remarkably durable Maya Blue — indigo and an unusual clay mineral called palygorskite. Since multiple studies attempted to recreate the substance, it’s common knowledge that the chemical bond can be formed through heating the concoction.

Yet evidence of how or where the pigment was manufactured centuries ago has been sorely lacking — until now.

According to Arnold’s research findings, published this month in the journal Antiquity, Mayans fused together the mixture of indigo leaves and palygorskite in ceramic bowls over burning copal incense alongside a natural well in the Yucatan. The creation of Maya Blue was part of spiritual performance customs at the Sacred Cenote of Chichen Itza, a pre-Colombian archeological site built by the Mayans in present-day Mexico and one of the Seven Wonders of the Ancient World.

Sacrificial victims were drenched in the substance and thrust backward on a stone altar to have their beating hearts cut from their chests before being thrown into the Sacred Cenote, an enormous natural well considered a portal into the spiritual realm.

The pool was dredged in 1904 by American archeologist Edward H. Thompson, who unearthed more than 100 skeletons, as well as gifts of decorated rubber, wood, jugs, jars and pots that were tossed into its depths to please the rain god, Chaak, who was believed to reside there.

Since Arnold conducted field studies for his dissertation on the paint in the 1960s, he has been piecing together the puzzle, returning to the Yucatan 10 times in the course of just more than a decade and collecting palygorskite from different sites.

Recently, Wheaton College received grant money to have the samples analyzed to characterize the substance’s sources “with an eye to finding out where the blue came from.”

The scope of the undertaking widened when Arnold asked a graduate student to go through the inventory of pieces at the Field Museum to identify potential traces of Maya Blue — and then came the breakthrough.

“We saw an item that was a blue three-footed pottery bowl that had been in the museum’s possession for 75 years. It was down in a holding area for such-and-such exhibit, and we went to pull it,” Arnold said. “With gloves on, we turned it upside down and hardened copal (resin) fell out of the bowl and into my hand. With a hand lens, we could see palygorskite on the bottom.”

Further electron microscope scanning confirmed the presence of preserved bits of palygorskite and indigo, and the team of anthropologists traced the piece back, discovering it was dredged during Thompson’s expedition. A clearer picture of the dye’s history began to emerge as Arnold and company pinpointed the pigment’s location, which, coupled with indigo’s well-documented religious usages by priests, helped them to develop their thesis that Maya Blue was rife with holy undertones.

“The ritual combination of the specific elements of indigo, palygorskite and copal incense — each of which was therapeutic — at the edge of the Sacred Cenote was significant,” Arnold said. “The result was symbolic of the healing power of water in an agricultural community, and the bright color was intended to invoke rainfall and allow the corn to grow again.”

To bolster their arguments, the team compiled Mayan artwork, textual accounts and journals of Spanish colonizers that supported their conclusions about Maya Blue.

“This study documents the analytical value of museum collections for resolving long-standing research questions,” said Gary Feinman, co-author and curator of anthropology at the Field Museum. “(It) required documentary, ethnographic and experimental research to establish the full context and use of the artifacts.”

Until now, the 14-foot layer of blue precipitate found at the bottom of the Sacred Cenote when it was dredged seemed rather inconsequential, Arnold said. But the study offers evidence that it was remnants of the renowned Maya Blue. Hurried paint jobs in the throes of religious fervor caused the pigment to wash off of sacrificial items before the glaze dried and settle at the bottom because of the weight of the clay base.

Researchers plan to study other museum pieces to continue on in their quest to bring Mayan culture to light.

“This experience has been amazing,” Arnold said. “I’m just bowled over by it all. In awe by how the discovery has created a buzz all over the world.”

Suburban Life

The Maya mystery

Maya Blue has puzzled archaeologists, chemists and materials scientists since it was first identified in 1931 because of its unusual chemical stability, composition and persistent color in one of the world’s harshest climates.

It has proven to be resistant to age, acid, weathering, biodegradation and even modern chemical solvents.

Experts have dubbed Maya Blue one of the greatest technological and artistic achievements on Mesoamerica.